MSU Extension Irrigated Soybean PlotLyndon Kelley
MSU Extension / Purdue University Irrigation Management Agent St. Joseph Co. MSU Extension, 612 E. Main St., Centreville, MI 49032
Cell 269-535-0343, kellyl@msu.edu, 269-467-5511
• Soil pH
• N rate and timing
• Weed control
• Residue management
• Compaction issues
Irrigate to assure the best plant stand possible “It’s an ART”
• Irrigate, if necessary, to make sure to get maximum germination and uniform emergence. (Either before or after planting)
• ½ inch in most irrigated soil within five days of planting. Monitor crusting issues
• Maintain a moist surface, 0.10” to 0.20” applications, (rotary hoe if necessary).
Are you ready to irrigate the day you plant?
Timely application of irrigation water: • Improves incorporation of herbicides.
• Improves activation of herbicides.
• Reduces nitrogen volatilization.
(Water stressed weed to get better glyphosate kill)
Irrigation - think of your soil as a bank
Intake rate:
Deletion:
total water
water before it allow it to
pass lower down.
it’s roots.
Heavier soil can hold
more water / foot of
depth than light soils
Water lost from the bottom of the profile can wash out (leach)
water soluble nutrients and pesticides.
Summary
Based on the three years of data, it appears that maximizing soybean yields in Michigan is dependent on maintaining adequate soil moisture beginning at full bloom (R2) or beginning pod (R3), provided that the soil water deficit does not exceed 75% prior to that growth stage.
Waiting to irrigate until pod elongation (R3-R4)
maximized water use efficiency in two of the three years as long as the soil water deficit never reached 75%.
Soybean Physiology: How Well Do You Know Soybeans? Shaun Casteel, Purdue University -Soybean Extension Specialist
Summary – con’t
Waiting to irrigate until pod elongation (R3-R4) maximized water use efficiency in two of the three years as long as the soil water deficit never reached 75%.
In two of the three years, an emergency irrigation water application was required to prevent the soil water deficit from reaching 75% so waiting until pod elongation may not be recommended in some years.
Use data from irrigated soybean variety performance trials to select high-yielding, disease resistant/tolerant varieties that resist lodging to maximize irrigated soybean yields.
Summary of Irrigated Soybean Research in Michigan SMaRT Soybean Facts – 2/2011
MSU Excel Irrigation Schedule Checkbook Method - Mendon 2014
L e a c h
in g
(W il
Calculating Water Holding Capacity
Water Holding Capacity at 40% and 60% Threshold to Full (in Inches)
Soybeans rooting depth for scheduling purposes - 24”
Soil Type/Soil
40% 60% 40% 60% 40% 60% 40% 60%
0 to 6 0.50 0.34 0.72 0.48 0.45 0.30 0.32 0.22
0 to 12 1.02 0.68 1.44 0.96 0.90 0.60 0.65 0.43
0 to 18 1.56 1.04 2.03 1.36 1.42 0.95 0.97 0.65
0 to 24 2.10 1.40 2.63 1.75 1.98 1.32 1.30 0.86
0 to 30 2.88 1.92 3.22 2.15 2.54 1.69 1.55 1.03
20% increase in Water Holding Capacity
Soil Type
Soybeans rooting depth - 24”
20% increase in Water Holding Capacity plus one weeks soybean water use at R3 stage
0.15” x 7 days = 1.05”
Soil Type
24” 2.5” 2.6” 2.4” 2.1”
Limited Water Supply Irrigation Management
Diversify the crops sharing the water supply between high and low water use. (? Potato and soybeans ?)
Diversify the crops sharing the water supply and peak water use times (? corn and soybeans ?)
• Start irrigating early to bank water ahead. (Soybeans lack rooting depth to make bank ahead work well)
Nebraska limited water plan:
Ideal Irrigation Application Volume
• never wet below the root zone
• large enough to minimize the number of times soil surface and crop are wetted.
(save water / reduce disease)
• July 0.5” to 0.7”
• August 0.7” to 1.0”
• September 0.3” to 0.7”
Large Irrigation Applications Volume Deliver More Effective Water To Crop
• In a typical July a soybean crop E.T. will be 5.4”
• Evaporation varies greatly by canopy, crop residue and soil type
• The first 0.05” to 0.12”of each overhead application of water will evaporate from soil surface and crop canopy.
Effective water based on a 0.08” evaporation / application
Water evaporated from crop canopy & soil surface
Effective water available for crop transpiration
Six applications of 0.90”
Eighteen applications of 0.30” 1.44” 3.96”
Small irrigation applications volume will require more total water to get equal water to crop
http://water.unl.edu/cropswater/nawmdn
Irrigation Threshold
Monitoring soil wetted front -12 hrs. after irrigation
½” into dry soil ½” into moist soil 1” into dry soil 1” into moist soil
If your 1” application did not go down as far down as it did last week ???
- your not keeping up.
Catch Can Volume (ml)
Distance from Pivot (ft)
lodged areas